If you have enough for game or slam, just bid it (or use Blackwood). You can also respond with a new suit (forcing). If you are interested in game and want to know more about partner's hand, respond 2NT (see Larry's article on FEATURE).

But, in most cases, you won't have game interest. Should you pass? Not if you have 3+ card support. Raise to the appropriate LAW of Total Tricks level.

With 3-card support, you know your side has 9 trumps. Raise to 3. This is not invitational (you didn't bid 2NT).

With 4-card support, raise to the 4-level (10 trumps).

Follow this advice blindly? No. If you are vulnerable and/or very flat (4-3-3-3) and/or full of queens/jacks, you don't have to do it!

Pass. You have no game interest (opposite 6-10 and with a misfit, your partner will be lucky if he can make 2). The "LAW" actually says to bid 1 (7 trumps), but that it illegal. Speaking of "illegal," wouldn't it be nice if we could make a takeout double of partner's opening bid?

3. Your 9 trumps (and probably useful singleton) suggest your side is safe at the 3 level. Even if you go down, it will be a good sacrifice. Meanwhile, your raise makes it tough on West. Maybe he has, say,

Q54 Q8765 43 K82. He would have been happy bidding 3, but won't want to bid 4.